B1480

DTC B1480

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B1480 00
- Battery Rundown Protection Circuit

Diagnostic Fault Information






Circuit/System Description

Battery voltage is supplied at all times to the body control module (BCM) from the 15A INT LTS/PNL DIM fuse located in the underhood fuse block. The BCM then applies this voltage to the following lamps:

* Dome/Reading Lamp
* Vanity Mirror Lamps
* Reading Lamp Assembly
* Inside Rearview Mirror
* Rear Compartment Courtesy Lamp

In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamps supply voltage circuit to prevent a total battery discharge condition.

Conditions for Running the DTC

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

The BCM detects a short ground on the inadvertent power courtesy lamp control circuit.

Action Taken When the DTC Sets

The BCM will deactivate inadvertent power to the courtesy lamps.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

Circuit/System Testing

1. Ignition OFF, disconnect the X3 harness connector at the BCM.
2. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 2 and ground.

^ If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit and components listed below for a short to ground. If all circuits and components test normal, replace the BCM.

3. Ignition OFF, connect the X3 harness connector at the BCM.
4. Disconnect the harness connector at each component listed below:

* Dome/reading Lamp
* Left Vanity Mirror Lamp
* Right Vanity Mirror Lamp
* Reading Lamp Assembly
* Inside Rearview Mirror Lamp
* Rear Compartment Courtesy Lamp

5. Ignition ON, verify a test lamp illuminates between the control circuit at each component harness connector and ground.

^ If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the BCM.

6. Connect each component one at a time and verify with a scan tool if the DTC resets as current.

^ If the DTC resets, test or replace the inoperative component.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Headlamp Switch Replacement (Impala)
* Sunshade Illuminated Mirror Lamp Bulb Replacement
* Sunshade Replacement
* Instrument Panel Courtesy Lamp Bulb Replacement
* Dome Lamp Replacement (Impala)
* Inside Rearview Mirror Replacement
* Rear Compartment Courtesy Lamp Replacement.